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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 90 |
| 4 | 1679 |
| 5 | 40977 |
| 6 | 1234002 |
| 7 | 44162294 |
| 8 | 1829650545 |
| 9 | 86075951647 |
| 10 | 4530650659261 |
| 11 | 263702502327536 |
| 12 | 16811827814422092 |
| 13 | 1164790943838593160 |
| 14 | 87124861733813622130 |
| 15 | 6995992413536990011830 |
| 16 | 600147439879762402873285 |
| 17 | 54768109160914827946501375 |
| 18 | 5297131818511043862499262665 |
[1,1,7,90,1679,40977,1234002,44162294,1829650545, 86075951647,4530650659261,263702502327536, 16811827814422092,1164790943838593160, 87124861733813622130,6995992413536990011830, 600147439879762402873285, 54768109160914827946501375, 5297131818511043862499262665] |